CA1168474A - Forward-reverse changeover apparatus for working vehicle - Google Patents
Forward-reverse changeover apparatus for working vehicleInfo
- Publication number
- CA1168474A CA1168474A CA000402095A CA402095A CA1168474A CA 1168474 A CA1168474 A CA 1168474A CA 000402095 A CA000402095 A CA 000402095A CA 402095 A CA402095 A CA 402095A CA 1168474 A CA1168474 A CA 1168474A
- Authority
- CA
- Canada
- Prior art keywords
- gear
- input
- shaft
- output
- clutch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
- F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
- F16H3/08—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts
- F16H3/14—Gearings for reversal only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
- F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
- F16H3/16—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion essentially with both gears that can be put out of gear and continuously-meshing gears that can be disengaged from their shafts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H2700/00—Transmission housings and mounting of transmission components therein; Cooling; Lubrication; Flexible suspensions, e.g. floating frames
- F16H2700/02—Transmissions, specially for working vehicles
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19219—Interchangeably locked
- Y10T74/19377—Slidable keys or clutches
- Y10T74/19386—Multiple clutch shafts
- Y10T74/194—Selective
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19219—Interchangeably locked
- Y10T74/19377—Slidable keys or clutches
- Y10T74/19386—Multiple clutch shafts
- Y10T74/19405—Multiple forward and reverse
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19219—Interchangeably locked
- Y10T74/19377—Slidable keys or clutches
- Y10T74/19386—Multiple clutch shafts
- Y10T74/19409—Single forward and reverse
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Structure Of Transmissions (AREA)
- Treatment Of Water By Ion Exchange (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A forward-reverse changeover apparatus for working vehi-cles comprises first and second multiplate clutches, and an input and output shaft arranged concentrically with and separated from each other. Output gears extending from the first and second clutches respectively have the same number of teeth, and the out-put gear from the second clutch is positioned closer to the input shaft than an input gear on the output shaft.
A forward-reverse changeover apparatus for working vehi-cles comprises first and second multiplate clutches, and an input and output shaft arranged concentrically with and separated from each other. Output gears extending from the first and second clutches respectively have the same number of teeth, and the out-put gear from the second clutch is positioned closer to the input shaft than an input gear on the output shaft.
Description
~ '7~
This invention relates to a forward-reverse changeover apparatus for w~rking vehicles of the type compxising an input shaft, an outpu-t shaft arranged coaxially with and separated from the input shaft, first and second multiplate clutches rotatable about axes parallel to the input shaft, gears having the same number of teeth and coaxially rotatable with the first and second clutches respectively for giving an input to the clutches indiv-idually, the gears meshing with an output gear on the input shaft at different positions along the circumference of the output gear, an input gear mounted on the output shaft and meshing with an output gear rotatable coaxially with an output member extending from the first clutch, and an output gear rotatable coaxially with an output member extending from the second clutch and meshing with a reverse rotation gear, the input gear on the output shaft being in mesh with the reverse rotation gear.
Such a forward-reverse changeover apparatus heretofore known is adapted to effect forward-reverse changeover easily and rapidly by advantageously using the first and second multiplate clutches. The first and second clutches are arranged at different positions along the circumference of the output gear on the input shaft to reduce the axial length of the input shaft as well as of the output shaft. The conventional apparatus, however, has the disadvantage of having different forward and reverse speeds.
With the conventional arrangement, the output gear extending from the second clutch for reverse transmission and the input gear on the output shaft are located at the same posi-tion with respect to the axis of the output shaft, so that in order to avoid simultaneous meshing of the output gear of the second clutch and the above-mentioned reverse rotation gear with the input gear on the output shaft, the output gear used for the second clutch is smaller in diameter and tooth number than the output gear extending from the first clutch for forward trans-~ ~ ' b mission. For this reason, the above disadvantage has been ex-perienced.
An object of the present invention is to provide the same output speed in the forward position and in the reverse po-sition, with attention directed to the different frequencies with which the two clutches are actually used, without usiny an input ; shaft or ou-tput shaft of increased axial length.
Accordingly, the present invention provides a forward-; reverse changeover apparatus for a working vehicle, comprising an input shaft, an output shaft coaxial with and separated from theinput shaft, first and second multiplate clutches rotatable about axes parallel to the input shaft, first and second input gears having the same number of teeth and coaxially rotatable with the first and second clutches respectively for providing an input to the clutches individually, said first and second input gears meshing with a first output gear on the input shaft at different positions along the circumference of the first output gear, a third input gear mounted on the output shaft and meshing with second output gear rotatable coaxially with an output member ex-tending from the first clutch and a third output gear rotatablecoaxially with an output member extending from the second clutch and meshing with a reverse rotation gear, the third input gear being in mesh with the reverse rotation gear, the second and third output gears having substantially the same number of teeth, and the third output gear being positioned closer to the input shaft than the third input gear.
Working vehicles are operated chiefly in the forward position with the second clutch for reverse transmission used ~ much less frequently than the first clutch for forward transmis-; 30 sion, so that the second clutch can have less frictional trans-- mission plates than the first clutch wil:hout causing any particu-lar trouble in actualoperation. ~ith attention focused on this point, the output gear extending from the second clutch is posi-tioned closer to the input shaft than the input gear on the out put shaft. This avoids simultaneous meshing of the outpu-t gear extending from the second clutch and the reverse rotation gear with the input gear on the output shaft. The same output speed is made available in the forward position and in the reverse position without using an input shaft or output shaft of increas-ed axial length because the output gears extending from the first and second clutches have substantially the same number of teeth.
Thus the forward-reverse changeover apparatus is very useful for working vehicles.
The invention will now be described in more detail, by way of example only, with reference to the accompanying draw-ings, in which:-Fig. 1 is a side elevation schematically showing atransmission system;
Fig. 2 is a side elevation in vertical section and development showing the forward-reverse changeover apparatus;
Fig. 3 is a side elevation in vertical section showing an auxiliary speed change mechanism; and Fig. 4 is a front view showing connecting blocks.
The drawings show the power transmission system of an agricultural tractor including an engine 1, a main clutch housing
This invention relates to a forward-reverse changeover apparatus for w~rking vehicles of the type compxising an input shaft, an outpu-t shaft arranged coaxially with and separated from the input shaft, first and second multiplate clutches rotatable about axes parallel to the input shaft, gears having the same number of teeth and coaxially rotatable with the first and second clutches respectively for giving an input to the clutches indiv-idually, the gears meshing with an output gear on the input shaft at different positions along the circumference of the output gear, an input gear mounted on the output shaft and meshing with an output gear rotatable coaxially with an output member extending from the first clutch, and an output gear rotatable coaxially with an output member extending from the second clutch and meshing with a reverse rotation gear, the input gear on the output shaft being in mesh with the reverse rotation gear.
Such a forward-reverse changeover apparatus heretofore known is adapted to effect forward-reverse changeover easily and rapidly by advantageously using the first and second multiplate clutches. The first and second clutches are arranged at different positions along the circumference of the output gear on the input shaft to reduce the axial length of the input shaft as well as of the output shaft. The conventional apparatus, however, has the disadvantage of having different forward and reverse speeds.
With the conventional arrangement, the output gear extending from the second clutch for reverse transmission and the input gear on the output shaft are located at the same posi-tion with respect to the axis of the output shaft, so that in order to avoid simultaneous meshing of the output gear of the second clutch and the above-mentioned reverse rotation gear with the input gear on the output shaft, the output gear used for the second clutch is smaller in diameter and tooth number than the output gear extending from the first clutch for forward trans-~ ~ ' b mission. For this reason, the above disadvantage has been ex-perienced.
An object of the present invention is to provide the same output speed in the forward position and in the reverse po-sition, with attention directed to the different frequencies with which the two clutches are actually used, without usiny an input ; shaft or ou-tput shaft of increased axial length.
Accordingly, the present invention provides a forward-; reverse changeover apparatus for a working vehicle, comprising an input shaft, an output shaft coaxial with and separated from theinput shaft, first and second multiplate clutches rotatable about axes parallel to the input shaft, first and second input gears having the same number of teeth and coaxially rotatable with the first and second clutches respectively for providing an input to the clutches individually, said first and second input gears meshing with a first output gear on the input shaft at different positions along the circumference of the first output gear, a third input gear mounted on the output shaft and meshing with second output gear rotatable coaxially with an output member ex-tending from the first clutch and a third output gear rotatablecoaxially with an output member extending from the second clutch and meshing with a reverse rotation gear, the third input gear being in mesh with the reverse rotation gear, the second and third output gears having substantially the same number of teeth, and the third output gear being positioned closer to the input shaft than the third input gear.
Working vehicles are operated chiefly in the forward position with the second clutch for reverse transmission used ~ much less frequently than the first clutch for forward transmis-; 30 sion, so that the second clutch can have less frictional trans-- mission plates than the first clutch wil:hout causing any particu-lar trouble in actualoperation. ~ith attention focused on this point, the output gear extending from the second clutch is posi-tioned closer to the input shaft than the input gear on the out put shaft. This avoids simultaneous meshing of the outpu-t gear extending from the second clutch and the reverse rotation gear with the input gear on the output shaft. The same output speed is made available in the forward position and in the reverse position without using an input shaft or output shaft of increas-ed axial length because the output gears extending from the first and second clutches have substantially the same number of teeth.
Thus the forward-reverse changeover apparatus is very useful for working vehicles.
The invention will now be described in more detail, by way of example only, with reference to the accompanying draw-ings, in which:-Fig. 1 is a side elevation schematically showing atransmission system;
Fig. 2 is a side elevation in vertical section and development showing the forward-reverse changeover apparatus;
Fig. 3 is a side elevation in vertical section showing an auxiliary speed change mechanism; and Fig. 4 is a front view showing connecting blocks.
The drawings show the power transmission system of an agricultural tractor including an engine 1, a main clutch housing
2, a transmission case 3, an intermediate case 4, and a differ-ential gear case 5, which are connected together in series in the order mentioned. The power of the engine is subjected to suit-able gear speed change within the cases and is delivered to rear wheel drive shafts 6, 6 on the opposite sides of the differential gear case 5, to a transmission shaft 7 supported by the bottom of the transmission case 3 and extending forward for driving - the front wheels, and to a PTO shaft 8 projecting rearward from the case 5.
An intermediate transmission chamber A is provided be-tween and defined by the front wall 3a of the transmission case
An intermediate transmission chamber A is provided be-tween and defined by the front wall 3a of the transmission case
3 and the rear wall 2a of the main clutch housing 2. A main speed change chamber B for the running system is provided behind the chamber A. The interior of the intermediate case 4 serves as a PTO speed change chamber C. An auxiliary speed change cham-ber D for the running system is formed in the front half of the differential gear case 5, and a differential speed change chamber E in the rear half thereof.
The main speed change chamber B has a speed change shaft 9, an input shaft 10 serving as an output shaft for the forward-reverse changeover apparatus -to be described later, and a first intermediate transmission shaft 11 for the PTO system.
These shafts are arranged one above another in parallel. The in-put shaft 10 is fixedly provided with four gears 12a, 12b, 12c, 12d which are different in diameter. Speed change gears 13a, 14a meshing with the first gear 12a and the fourth gear 12d on the input shaft 10 respectively are freely rotatably mounted by spline bosses 13b, 14b on the speed change shaft 9. A pair of shift gears 15, 16 is splined to the shaft 9. The first shift gear 15 gives a first speed when shifted rearward and fittingly joined to the spline boss 13b of the gear 13a. When shifted for-ward and directly meshed with the second gear 12b, the first shift gear 15 affords a second speed. The second shift gear 16 gives a third speed when shifted rearward into direct meshing engagement with the third gear 12c, or a fourth speed when shift-ed forward and fittingly joined to the spline boss 14b of the speed change gear 14a. In this way, a main speed change mechanism 17 is constructed. An interconnecting shaft 18 coupled to the rear end of the speed change shaft 9 coaxially therewith extends into an upper portion of the PTO speed change chamber C.
The PTO speed change chamber C has the interconnecting shaft 18, a speed change shaft 19, and the PTO shaft 8, as arrang-ed one above another in parallel. The speed change shaft 19 is coaxial with the input sha~t 10. The PTO shaft 8 is disposed in end-to-end relation to a second intermediate transmission shaft 20, which is coupled at its front end to the rear end of the first intermediate transmission shaft 11 for the PTO system.
The speed change shaft 19 is operatively connected to the second intermediate shaft 20 by reduction gears 21, 22. A shift gear 23 splined to the front end of the PTO shaft 8 is rearwardly shiftable to mesh with a small gear 2~ fixedly mounted on the shaft 19, whereby the PTO shaft 8 is driven at a low speed. When the shift gear 23 is shifted forward and splined directly to the rear end of the second intermediate shaft 20, the PTO shaft 8 is driven at the same speed as the shaft 20. Thus a PTO speed change mechanism 25 is constructed.
The auxiliary speed change chamber D is provided with a speed change shaft 27 coaxially coupled to the rear end of the interconnecting shaft 18, a bevel pinion shaft 29 operatively connected to a differential speed change mechanism 28, and the PTO shaft 8. These shafts are arranged one above another in para-llel. Like the speed change shaft 19 of the PTO speed change mechanism 25, the bevel pinion shaft 29 is in alignment with the input shaft 10. A double gear composed of shift gears 30a, 30b and splined to the bevel pinion shaft 29 affords a low speed when shifted forward to mesh the shift gear 30a with a small gear 31 fixed to the speed change shaft 27. When the double gear is shifted rearward to mesh the shift gear 30b with a large gear 32 on the shaft 27, a high speed is available. Thus an auxiliary speed change mechanism 33 is constructed.
The differential gear case 5 has a bo-ttom opening 80 which is externally provided with cl transmission case 81 support-ing the transmission shaft 7 for driving the front wheels. A
shift gear 82 splined to the transmission shaft 7 is projected into the case 5 through the opening 80. A gear 83 fixed to the terminal speed change shaft, namely the bevel pinion shaft 29, meshes with an idle gear 84 supported on the PTO shaft 8. The shift gear 82 is meshable with and disengageable from a gear 85 integral with the gear 84. The shift gear 82, when shifted, runs the tractor by four-wheel drive or rear-wheel drive alter-natively. Fig. 3 further shows a transmission shaft 86 extending to a differential speed change mechanism for the front wheels and a shaft cover 87. When the tractor is driven by the rear wheels only, the opening 80 is closed with a cover in place of the transmission case 81.
An apparatus of the hydraulic clutch type for forward-reverse changeover is installed in the intermediate transmission chamber A as will be described below in detail.
Extending into the chamber A is the front end of the running system input shaft lO corresponding to the output shaft of the changeover apparatus. The apparatus is disconnectably coupled to the engine l by a main clutch 34 for power transmission and has an input shaft 35, the rear end of which is coaxial with and separated from the front end of the input shaft lO within the chamber A. First and second multiplate clutches 37, 36 are arranged below and above these shafts 10, 35. Intermediate trans-mission shafts 38, 39 rotatable about axes parallel to the shafts lO, 35 are supported on the main clutch housing rear wall 2a and a bracket 40 attached to the wall.
The second clutch 36 in the upper position comprises a drive drum 41 fixed to the intermediate shaft 38, a piston 42 housed in the drum 41, a driven drum 43 freely rotatably mounted on the shaft 38 and frictional transmission plates 44... , 45 provided between the drums 41 and 43. The piston 42, when shifted rightward with pressure oil, presses the plates 44 into contact with the plates 45 to transmit power from the drum 41 to the drum 43. When freed from the hydraulic pressure, the piston 42 is returned leftward by a spring 46 to interrupt the power trans-mission, An input gear 47 fixed to the drive drum 41 is in mesh w~th an output gear 48 fixedly mounted on the rear end of the input shaft 35. An output gear 49 integral with the driven drum 43 is in mesh with a reverse rotation gear 51 of large width which is freely rotatably supported by a shaft 50 within the in-termediate,transmission chamber A and which is in mesh with an input gear 52 secured to the front end of the output shaft 10 to couple the gear 49 to the gear 52. Like the second clutch 36, the first clutch 37 in the lower position comprises a drive drum 53, a driven drum 54, a piston 55, frictional transmission plates 56.., 57.., and a return spring 58. An input gear 59 attached to the drive drum 53 meshes with the output gear 48, while an output gear 60 integral with the driven drum 54 meshes directly with the input gear 52. The lower first clutch 37 is used for the transmission of positive rotation (forward transmis-sion), and the upper second clutch 36 for the transmission of reverse rotation (reverse transmission). The input gears 59, 47 for the first and second clutches 37, 36 have substantially the same number of teeth, and the output gears 60, 49 for the first and second clutches 37, 36 also have substantially the same number of tee-th. The output gear 49 connected to the second clutch 36 is positioned closer to the input shaft 35 than the input gear 52 on the output shaft 10. The number of the friction plates 56, 57 included in the first clutch 37 is equal to that of the fric-: tion plates 44, 45 included in the second clutch 36. Consequently the apparatus is adapted to giYe the same output speed in the forward position and in the re~erse position and is also pre-vented from delivering an unnecessary output when both the first and second clutches are in a disengaged sta-te. The contemplated object of the invention can be achieved even when the input gears 59, 47, as well as the out~ut gears 60, 49, slightly differ in tooth number.
The rear end of the lower intermediate transmission shaft 39 is connected in the chamber B to the first lntermediate transmlsslon shaft 11 of the PTO system by a coupling to transmit the power to the shaft 11 independently of the operation of the clutches 36, 37.
The pressure oll is supplied to and discharged from the clutches 36, 37 through internal oil channels 61, 62 extending through the intermediate transmission shafts 38, 39. The ends of these shafts 38, 39 projecting into the main clutch chamber F are provided with rotary joints 63, 64, which are connected by blocks 66, 67 to a control valve 65 mounted on the top of the main clutch housing 2. The connecting blocks 66, 67 have internal oil chan-nels.
- The control valve 65 is of the rotary type and has an operating arm 68 which is coupled by a release wire 71 to a for-ward-reverse changeover lever 70 provided in the vicinity of a steering wheel 69.
As will be apparent from the foregoing description, the transmission system has as arranged in series the forward-reverse changeover mechanism of the hydraulic clutch type to be controlled by the changeover lever 70, the main speed change mechanism 17 to be operated by a main speed change lever 72 for giving four different speeds, and the auxiliary speed change mechanism 33 to be operated by an unillustrated auxiliary speed change lever for affording two different speeds. Thus the system gives eight forward speeds and eight reverse speeds at the speed ratios pro-vided by these mechanisms.
Furthermore the output gear 49 connected to the secondmulitplate clutches 36 is positioned closer to the input shaft 35 than the input gear 52 on the output shaft 10 to thereby avoid simultaneoùs meshing of the output gear 49 of the second clutch 36 and the reverse rotation gear 51 with the input gear 52 on the ~
output shaft 10, whereas the same output speed is made available in the forward position and in the ~everse position because the output gears of the first and second clutches have substantially the same number of teeth.
In the case where first and second multiplate clutches which are different in the number of frictional transmission plates are used as conventionally practiced, the transmission plates are brought into contact with one another by being subjected to an external force when the clutch is engaged, and the plates are re-- lieved of the force when the clutch is disengaged but they still remain in contact with one another even in the disengaged state.
Accordingly even lf both the first and second clutches are in the disengaged state, the clutch which is the larger in the number of transmission plates deliver$ an unnecessary output. This en-tails the drawback, for example, of adversely affecting the con-trol of the gear speed change mechanisms to which the power is transmitted from the changeover apparatus or inadvertently advanc-ing the tractor.
However, the construction of the embodiment described above is free of any of such drawbacks and is therefore very use-ful because the frictional transmission plates 56, 57 included in the first clutch 37 are made equal in number to the number of the plates 44, 45 included in the second clutch 36 although the output gear 49 coupled to the second clutch 37 is positioned closer to the input shaft.
In embodying the present invention, the means for oper-ating the first and second clutches 37, 36 can be modified vari-ously. For example, a force doubling cam mechanism is useful for manually engaging and d~sengaging these clutches~
_ The present invention is useful for various ~orking vehicles including mova~le agricultural machines, such as combines and transport ve~icles, and construction machines, such as back-hoes and front loaders.
., - lQ -
The main speed change chamber B has a speed change shaft 9, an input shaft 10 serving as an output shaft for the forward-reverse changeover apparatus -to be described later, and a first intermediate transmission shaft 11 for the PTO system.
These shafts are arranged one above another in parallel. The in-put shaft 10 is fixedly provided with four gears 12a, 12b, 12c, 12d which are different in diameter. Speed change gears 13a, 14a meshing with the first gear 12a and the fourth gear 12d on the input shaft 10 respectively are freely rotatably mounted by spline bosses 13b, 14b on the speed change shaft 9. A pair of shift gears 15, 16 is splined to the shaft 9. The first shift gear 15 gives a first speed when shifted rearward and fittingly joined to the spline boss 13b of the gear 13a. When shifted for-ward and directly meshed with the second gear 12b, the first shift gear 15 affords a second speed. The second shift gear 16 gives a third speed when shifted rearward into direct meshing engagement with the third gear 12c, or a fourth speed when shift-ed forward and fittingly joined to the spline boss 14b of the speed change gear 14a. In this way, a main speed change mechanism 17 is constructed. An interconnecting shaft 18 coupled to the rear end of the speed change shaft 9 coaxially therewith extends into an upper portion of the PTO speed change chamber C.
The PTO speed change chamber C has the interconnecting shaft 18, a speed change shaft 19, and the PTO shaft 8, as arrang-ed one above another in parallel. The speed change shaft 19 is coaxial with the input sha~t 10. The PTO shaft 8 is disposed in end-to-end relation to a second intermediate transmission shaft 20, which is coupled at its front end to the rear end of the first intermediate transmission shaft 11 for the PTO system.
The speed change shaft 19 is operatively connected to the second intermediate shaft 20 by reduction gears 21, 22. A shift gear 23 splined to the front end of the PTO shaft 8 is rearwardly shiftable to mesh with a small gear 2~ fixedly mounted on the shaft 19, whereby the PTO shaft 8 is driven at a low speed. When the shift gear 23 is shifted forward and splined directly to the rear end of the second intermediate shaft 20, the PTO shaft 8 is driven at the same speed as the shaft 20. Thus a PTO speed change mechanism 25 is constructed.
The auxiliary speed change chamber D is provided with a speed change shaft 27 coaxially coupled to the rear end of the interconnecting shaft 18, a bevel pinion shaft 29 operatively connected to a differential speed change mechanism 28, and the PTO shaft 8. These shafts are arranged one above another in para-llel. Like the speed change shaft 19 of the PTO speed change mechanism 25, the bevel pinion shaft 29 is in alignment with the input shaft 10. A double gear composed of shift gears 30a, 30b and splined to the bevel pinion shaft 29 affords a low speed when shifted forward to mesh the shift gear 30a with a small gear 31 fixed to the speed change shaft 27. When the double gear is shifted rearward to mesh the shift gear 30b with a large gear 32 on the shaft 27, a high speed is available. Thus an auxiliary speed change mechanism 33 is constructed.
The differential gear case 5 has a bo-ttom opening 80 which is externally provided with cl transmission case 81 support-ing the transmission shaft 7 for driving the front wheels. A
shift gear 82 splined to the transmission shaft 7 is projected into the case 5 through the opening 80. A gear 83 fixed to the terminal speed change shaft, namely the bevel pinion shaft 29, meshes with an idle gear 84 supported on the PTO shaft 8. The shift gear 82 is meshable with and disengageable from a gear 85 integral with the gear 84. The shift gear 82, when shifted, runs the tractor by four-wheel drive or rear-wheel drive alter-natively. Fig. 3 further shows a transmission shaft 86 extending to a differential speed change mechanism for the front wheels and a shaft cover 87. When the tractor is driven by the rear wheels only, the opening 80 is closed with a cover in place of the transmission case 81.
An apparatus of the hydraulic clutch type for forward-reverse changeover is installed in the intermediate transmission chamber A as will be described below in detail.
Extending into the chamber A is the front end of the running system input shaft lO corresponding to the output shaft of the changeover apparatus. The apparatus is disconnectably coupled to the engine l by a main clutch 34 for power transmission and has an input shaft 35, the rear end of which is coaxial with and separated from the front end of the input shaft lO within the chamber A. First and second multiplate clutches 37, 36 are arranged below and above these shafts 10, 35. Intermediate trans-mission shafts 38, 39 rotatable about axes parallel to the shafts lO, 35 are supported on the main clutch housing rear wall 2a and a bracket 40 attached to the wall.
The second clutch 36 in the upper position comprises a drive drum 41 fixed to the intermediate shaft 38, a piston 42 housed in the drum 41, a driven drum 43 freely rotatably mounted on the shaft 38 and frictional transmission plates 44... , 45 provided between the drums 41 and 43. The piston 42, when shifted rightward with pressure oil, presses the plates 44 into contact with the plates 45 to transmit power from the drum 41 to the drum 43. When freed from the hydraulic pressure, the piston 42 is returned leftward by a spring 46 to interrupt the power trans-mission, An input gear 47 fixed to the drive drum 41 is in mesh w~th an output gear 48 fixedly mounted on the rear end of the input shaft 35. An output gear 49 integral with the driven drum 43 is in mesh with a reverse rotation gear 51 of large width which is freely rotatably supported by a shaft 50 within the in-termediate,transmission chamber A and which is in mesh with an input gear 52 secured to the front end of the output shaft 10 to couple the gear 49 to the gear 52. Like the second clutch 36, the first clutch 37 in the lower position comprises a drive drum 53, a driven drum 54, a piston 55, frictional transmission plates 56.., 57.., and a return spring 58. An input gear 59 attached to the drive drum 53 meshes with the output gear 48, while an output gear 60 integral with the driven drum 54 meshes directly with the input gear 52. The lower first clutch 37 is used for the transmission of positive rotation (forward transmis-sion), and the upper second clutch 36 for the transmission of reverse rotation (reverse transmission). The input gears 59, 47 for the first and second clutches 37, 36 have substantially the same number of teeth, and the output gears 60, 49 for the first and second clutches 37, 36 also have substantially the same number of tee-th. The output gear 49 connected to the second clutch 36 is positioned closer to the input shaft 35 than the input gear 52 on the output shaft 10. The number of the friction plates 56, 57 included in the first clutch 37 is equal to that of the fric-: tion plates 44, 45 included in the second clutch 36. Consequently the apparatus is adapted to giYe the same output speed in the forward position and in the re~erse position and is also pre-vented from delivering an unnecessary output when both the first and second clutches are in a disengaged sta-te. The contemplated object of the invention can be achieved even when the input gears 59, 47, as well as the out~ut gears 60, 49, slightly differ in tooth number.
The rear end of the lower intermediate transmission shaft 39 is connected in the chamber B to the first lntermediate transmlsslon shaft 11 of the PTO system by a coupling to transmit the power to the shaft 11 independently of the operation of the clutches 36, 37.
The pressure oll is supplied to and discharged from the clutches 36, 37 through internal oil channels 61, 62 extending through the intermediate transmission shafts 38, 39. The ends of these shafts 38, 39 projecting into the main clutch chamber F are provided with rotary joints 63, 64, which are connected by blocks 66, 67 to a control valve 65 mounted on the top of the main clutch housing 2. The connecting blocks 66, 67 have internal oil chan-nels.
- The control valve 65 is of the rotary type and has an operating arm 68 which is coupled by a release wire 71 to a for-ward-reverse changeover lever 70 provided in the vicinity of a steering wheel 69.
As will be apparent from the foregoing description, the transmission system has as arranged in series the forward-reverse changeover mechanism of the hydraulic clutch type to be controlled by the changeover lever 70, the main speed change mechanism 17 to be operated by a main speed change lever 72 for giving four different speeds, and the auxiliary speed change mechanism 33 to be operated by an unillustrated auxiliary speed change lever for affording two different speeds. Thus the system gives eight forward speeds and eight reverse speeds at the speed ratios pro-vided by these mechanisms.
Furthermore the output gear 49 connected to the secondmulitplate clutches 36 is positioned closer to the input shaft 35 than the input gear 52 on the output shaft 10 to thereby avoid simultaneoùs meshing of the output gear 49 of the second clutch 36 and the reverse rotation gear 51 with the input gear 52 on the ~
output shaft 10, whereas the same output speed is made available in the forward position and in the ~everse position because the output gears of the first and second clutches have substantially the same number of teeth.
In the case where first and second multiplate clutches which are different in the number of frictional transmission plates are used as conventionally practiced, the transmission plates are brought into contact with one another by being subjected to an external force when the clutch is engaged, and the plates are re-- lieved of the force when the clutch is disengaged but they still remain in contact with one another even in the disengaged state.
Accordingly even lf both the first and second clutches are in the disengaged state, the clutch which is the larger in the number of transmission plates deliver$ an unnecessary output. This en-tails the drawback, for example, of adversely affecting the con-trol of the gear speed change mechanisms to which the power is transmitted from the changeover apparatus or inadvertently advanc-ing the tractor.
However, the construction of the embodiment described above is free of any of such drawbacks and is therefore very use-ful because the frictional transmission plates 56, 57 included in the first clutch 37 are made equal in number to the number of the plates 44, 45 included in the second clutch 36 although the output gear 49 coupled to the second clutch 37 is positioned closer to the input shaft.
In embodying the present invention, the means for oper-ating the first and second clutches 37, 36 can be modified vari-ously. For example, a force doubling cam mechanism is useful for manually engaging and d~sengaging these clutches~
_ The present invention is useful for various ~orking vehicles including mova~le agricultural machines, such as combines and transport ve~icles, and construction machines, such as back-hoes and front loaders.
., - lQ -
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A forward-reverse changeover apparatus for a working vehicle, comprising an input shaft, an output shaft coaxial with and separated from the input shaft, first and second multiplate clutches rotatable about axes parallel to the input shaft, first and second input gears having the same number of teeth and coaxi-ally rotatable with the first and second clutches respectively for providing an input to the clutches individually, said first and second input gears meshing with a first output gear on the input shaft at different positions along the circumference of the first output gear, a third input gear mounted on the output shaft and meshing with a second output gear rotatable coaxially with an out-put member extending from the first clutch and a third output gear rotatable coaxially with an output member extending from the second clutch and meshing with a reverse rotation gear, the third input gear being in mesh with the reverse rotation gear, the second and third output gears having substantially the same number of teeth, and the third output gear being positioned closer to the input shaft than the third input gear.
2. An apparatus as claimed in claim 1 wherein each of the first and second clutches includes frictional transmission plates, and the number of frictional transmission plates in the first clutch is equal to the number in the second clutch.
3. An apparatus as claimed in claim 1 wherein the first and second clutches are substantially identical with each other in construction.
4. An apparatus as claimed in claim 3 wherein the first clutch is provided between the first input gear and the second output gear, and the second clutch is provided between the second input gear and the third output gear.
5. An apparatus as claimed in claim 4 wherein the first and second input gears are provided in the vicinity of the rear wall of a main clutch housing, and the second and third output gears are provided in the vicinity of a bracket within a trans-mission case.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56155369A JPS5857549A (en) | 1981-09-29 | 1981-09-29 | Changeover device for forward and backward motion of service car |
| JP155369/1981 | 1981-09-29 | ||
| JP56201908A JPS58102848A (en) | 1981-12-14 | 1981-12-14 | Device for switching forward and backward motion of workig vehicle |
| JP201908/1981 | 1981-12-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1168474A true CA1168474A (en) | 1984-06-05 |
Family
ID=26483389
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000402095A Expired CA1168474A (en) | 1981-09-29 | 1982-04-30 | Forward-reverse changeover apparatus for working vehicle |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4484488A (en) |
| KR (1) | KR870001671Y1 (en) |
| AU (1) | AU537530B2 (en) |
| CA (1) | CA1168474A (en) |
| DE (1) | DE3218260A1 (en) |
| FR (1) | FR2513718B1 (en) |
| GB (1) | GB2106601B (en) |
| NO (1) | NO160312C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102797804A (en) * | 2012-09-03 | 2012-11-28 | 严晓龙 | Speed changing structure of power transmission device |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58188223U (en) * | 1982-05-21 | 1983-12-14 | 株式会社クボタ | Tractor transmission |
| US5408896A (en) * | 1993-03-30 | 1995-04-25 | Mtd Products Inc | Power transmission drive system |
| EP0953791B1 (en) * | 1998-04-29 | 2003-07-02 | Deere & Company | Gearshift device for a reversing gearbox |
| US6986295B2 (en) * | 2003-05-21 | 2006-01-17 | Kubota Corporation | Transmission for work vehicle having PTO function |
| JP5270269B2 (en) * | 2008-09-05 | 2013-08-21 | 株式会社Ｉｈｉシバウラ | Power transmission mechanism of walking lawn mower |
| WO2012043561A1 (en) * | 2010-09-28 | 2012-04-05 | 株式会社クボタ | Power transmission device of tractor |
| JP6570535B2 (en) * | 2014-09-29 | 2019-09-04 | 愛知機械工業株式会社 | Transmission and its assembly method |
| JP6904323B2 (en) * | 2018-11-28 | 2021-07-14 | 井関農機株式会社 | Work vehicle |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1316633A (en) * | 1919-09-23 | mum son | ||
| US1938855A (en) * | 1931-08-29 | 1933-12-12 | Toro Mfg Company | Reversing mechanism |
| US2117852A (en) * | 1935-11-18 | 1938-05-17 | Twin Diso Clutch Company | Hydraulically operated reversing mechanism |
| US2220542A (en) * | 1938-12-07 | 1940-11-05 | Carl D Peterson | Two speed forward and two speed reverse transmission |
| US2372733A (en) * | 1942-09-02 | 1945-04-03 | Borg Warner | Transmission |
| FR1075637A (en) * | 1952-03-13 | 1954-10-19 | Improvement in power transmission mechanisms | |
| DE1108571B (en) * | 1959-09-04 | 1961-06-08 | Bayerische Traktoren Und Fahrz | Vehicle transmissions, especially for tractors used in agriculture |
| DE1192901B (en) * | 1961-09-22 | 1965-05-13 | Camille Henri Masson | Reversing gear especially designed for marine propulsion |
| GB1128232A (en) * | 1965-01-19 | 1968-09-25 | Tadao Yamaoka | Reversing gear for marine main engine |
| GB1079156A (en) * | 1965-03-22 | 1967-08-16 | Tadao Yamoaka | Hydraulically operated reversing gear devices for marine internal-combustion engines |
| DE1950914C3 (en) * | 1969-10-09 | 1982-11-11 | Klöckner-Humboldt-Deutz AG, 5000 Köln | Switching device for switching a multi-stage gear change transmission driven by a switching disconnect clutch, in particular for agricultural tractors |
| DE2029572A1 (en) * | 1970-06-16 | 1971-12-23 | Klockner Humboldt Deutz AG, 5000 Köln | Engine that can be switched under load |
| DE2405023C2 (en) * | 1974-02-02 | 1982-07-08 | Klöckner-Humboldt-Deutz AG, 5000 Köln | Gear change transmissions in group design for motor vehicles, in particular for motor vehicles that can be used in agriculture and / or construction |
| IT1109610B (en) * | 1978-11-28 | 1985-12-23 | Fiat Trattori Spa | HIGH SPEED CHANGE OF SPEEDS FOR AGRICULTURAL TRACTORS AND SIMILAR VEHICLES |
-
1982
- 1982-04-20 AU AU82863/82A patent/AU537530B2/en not_active Ceased
- 1982-04-21 US US06/370,303 patent/US4484488A/en not_active Expired - Fee Related
- 1982-04-22 NO NO821305A patent/NO160312C/en unknown
- 1982-04-23 GB GB08211858A patent/GB2106601B/en not_active Expired
- 1982-04-30 CA CA000402095A patent/CA1168474A/en not_active Expired
- 1982-04-30 FR FR8207550A patent/FR2513718B1/en not_active Expired
- 1982-05-14 DE DE3218260A patent/DE3218260A1/en not_active Ceased
-
1986
- 1986-07-22 KR KR2019860010707U patent/KR870001671Y1/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102797804A (en) * | 2012-09-03 | 2012-11-28 | 严晓龙 | Speed changing structure of power transmission device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2106601B (en) | 1985-06-19 |
| NO821305L (en) | 1983-03-30 |
| GB2106601A (en) | 1983-04-13 |
| KR870001671Y1 (en) | 1987-05-06 |
| FR2513718A1 (en) | 1983-04-01 |
| FR2513718B1 (en) | 1986-01-31 |
| AU537530B2 (en) | 1984-06-28 |
| DE3218260A1 (en) | 1983-04-14 |
| NO160312C (en) | 1989-04-05 |
| NO160312B (en) | 1988-12-27 |
| AU8286382A (en) | 1983-08-18 |
| US4484488A (en) | 1984-11-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |